log.cpp

/*
 * log.cpp
 *
 * Copyright (C) 2011 Christoph Pfister <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "log.h"

#include <QMutex>
#include <QTextCodec>
#include <QTime>
#include <stdio.h>

class LogPrivate
{
public:
    LogPrivate() : position(0)
    {
        buffer.reserve(8176);
    }

    ~LogPrivate()
    {
    }

    void begin(const char *message)
    {
        mutex.lock();

        if (buffer.size() > (8176 - 1024)) {
            buffer.remove(0, buffer.indexOf(QLatin1Char('\n'), 1023) + 1);
        }

        position = buffer.size();
        buffer.append(QTime::currentTime().toString(Qt::ISODate));
        buffer.append(QLatin1Char(' '));
        buffer.append(QLatin1String(message));
    }

    void append(qint64 value)
    {
        buffer.append(QLatin1Char(' '));
        buffer.append(QString::number(value));
    }

    void append(quint64 value)
    {
        buffer.append(QLatin1Char(' '));
        buffer.append(QString::number(value));
    }

    void append(const QString &string)
    {
        buffer.append(QLatin1String(" \""));
        buffer.append(string);
        buffer.append(QLatin1Char('"'));
    }

    void end()
    {
        buffer.append(QLatin1Char('\n'));
        fprintf(stderr, "%s", QTextCodec::codecForLocale()->fromUnicode(
            buffer.constData() + position, buffer.size() - position).constData());
        mutex.unlock();
    }

    QMutex mutex;
    QString buffer;
    int position;
};

QString Log::getLog()
{
    if (data != NULL) {
        QMutexLocker locker(&data->mutex);
        return data->buffer;
    }

    return QString();
}

void Log::begin(const char *message)
{
    if (data == NULL) {
        LogPrivate *newData = new LogPrivate();

        if (!data.testAndSetOrdered(NULL, newData)) {
            // another thread won the battle
            delete newData;
        }
    }

    data->begin(message);
}

void Log::append(qint64 value)
{
    data->append(value);
}

void Log::append(quint64 value)
{
    data->append(value);
}

void Log::append(const QString &string)
{
    data->append(string);
}

void Log::end()
{
    data->end();
}

QBasicAtomicPointer<LogPrivate> Log::data = Q_BASIC_ATOMIC_INITIALIZER(0);